Metaphysical Semantics Meets Multiple Realizability

Sider’s Writing the Book of the World is an outstanding work. In an earlier review (Schaffer forthcoming) I called it ‘masterful ’ and ‘required reading’, while worrying about Sider’s notion(s) of structure. Here I offer the further praise of further discussion, centred on a separate worry concerning whether Sider’s metaphysical semantics can handle multiple realizability. Metaphysical semantics is supposed to connect the non-fundamental to the fundamental in a distinctively linguistic way, explaining how non-fundamen-tal truths can be grounded in fundamental facts, and so inducing a radically eliminative vision of the non-fundamental as mere talk. I wonder how the story goes when a single non-fundamental truth can be grounded in many different fundamental facts. For instance, the truth that Moore has hands can presumably be grounded in many different distributions of fields, arrange-ments of particles, vibrations of strings, or whatnot. I am asking how meta-physical semantics can accommodate this sort of multiple realizability. Multiple realizability came to prominence in philosophy of mind in th